Researchers at the University of California, San Diego School of Medicine say that a preference for geometric patterns early in life could be a signature behavior in infants who are at-risk for autism.
This preference was found in infants at-risk for autism as young as 14 months of age.
The researchers used eye-tracking methods to show that toddlers with autism spend significantly more time visually examining dynamic geometric patterns than they do looking at social images a viewing pattern not found in either typical or developmentally delayed toddlers.
"In testing 110 toddlers ages 14 to 42 months, we found that all of the toddlers who spent more than 69 percent of their time fixing their gaze on geometric images could be accurately classified as having an autism spectrum disorder or ASD," said Dr. Karen Pierce.
During this study, babies ranging in age between 12 and 42 months sat on their mother's lap as they watched a one-minute movie that contained shapes moving on one side of the screen (i.e., "dynamic geometric patterns) and children dancing and doing yoga on the other (i.e., "dynamic social images").
Using an infrared light beam that bounces off the eye, the researchers were able to measure what the baby liked to look at by measuring the amount of time they examined each side of the screen.
Interestingly, the dynamic geometric patterns that absorbed the attention of autistic but not normal babies, was nothing more than a common screen saver found on most computers.
Out of 51 typical infants in this study, only one preferred to look at the geometric images.
However, not all autistic toddlers preferred the geometric shapes. In the UCSD study, 40 percent of the ASD toddlers had this preference, compared to just two percent of the typical and nine percent of the developmentally delayed toddlers.
Thus, while 40 percent of the ASD toddlers were "geometric responders," the remaining 60 percent were similar to the typical and developmentally delayed groups in preferring dynamic social images.
"What an infant prefers to look at when given a choice between two images may turn out to be a more clearly observable indicator of autism risk than how he or she looks at a single image," said Pierce.
"Among toddlers who strongly prefer geometric patterns, we found that - almost 100 percent of the time - those children developed an autism spectrum disorder," he added.
The researchers concluded that a preference for moving geometric patterns, combined with how long toddlers stare when looking at moving geometric images, might be an early identifier of autism.
The study will be published in the latest issue of the Archives of General Psychiatry.